one of the many important pieces of the microsandbox runtime is metrics collection. it's been design to be crazy fast (shared memory), and extensible from ground up. all sandboxes write their metrics to a uniquely assigned memory slot. as sandboxes get destroyed, slots are re-assigned, and the slot's generation is bumped so readers can distinguish metrics from old vs new sandbox. new metrics entry replace previous ones. even at 1000 sandboxes on a single node (if ambitious), it consume merely 512kb of memory. runtime sampling is fully configurable, with option to switch off. the SDK, CLI and metrics exporter reads these metrics. the exporter provides an interface to register exporters to custom backends, as well as sampling rate. you're in full control. no reads or writes goes to the sqlite db. which means none of this gets in the hot path of starting a sandbox. you should never have to fly blind, whether it's a single or fleet of sandboxes. this is just one of the many optimizations we've done to do give you lightweight sandboxes that are also fast and extensible. i'll be posting more of these internals every now and then. next on my list is how we handle version negotiations with agentd (our custom init), to guarantee our SDKs runtime are backward compatible. p.s: i did a brief into of agentd in a prior post few weeks ag. check microsandbox.dev/blog.

native SSH support now in microsandbox@0.5. 🍻 previously, you'd run sshd inside the sandbox and expose a port. well, no more. point your existing ssh/sftp clients straight at it. available in all SDKs and CLI today. 🪅

early usage of opus 4.8, and it tells me: "hey we've been at this for 12 hours. let me add the task to the plan, and call it a night. if i continue, i'll likely introduce bugs due to fatigue". lol, not sure what to think of this. 😂

your sandboxed agent calls OpenAI. its transcript, secret placeholders included, ships to S3 for archival. a prompt injection tries to exfil keys, or at minimum fingerprint which credentials exist. a release pipeline tries to send $NPM_TOKEN somewhere weird. four scenarios, four different right answers. most sandbox providers stop at secret injection. that's 1 of 4. what about the other three? @microsandbox today gives you all 4. i dig into all the details in this article.